1. Field of the Invention
The present invention relates to a high-pressure tank filled with high-pressure gas. Specifically, it relates to a high-pressure tank capable of suppressing gas leaks easily and inexpensively under low temperature condition.
2. Related Art
Conventionally, a vehicle using high-pressure gas such as natural gas and hydrogen as fuel mounts a high-pressure tank filled with this gas. In this high-pressure tank, a rubber seal member such as an O-ring is installed to maintain the airtightness.
However, since this seal member is made of rubber, the seal member deteriorates when the temperature becomes an extremely low temperature (e.g. −50° C.), which causes the sealing properties to degrade. Accordingly, the gas may leak from the high-pressure tank. For example, when the vehicle mounting the above-mentioned high-pressure tank travels across a cold district, gas in a high-pressure tank is consumed as the travel distance increases, and then the pressure in the high-pressure tank decreases. Accordingly, gas remaining in the high-pressure tank expands, which causes the temperature to decrease to an extremely low temperature.
To solve this problem, it has been proposed that a technique for suppressing reduction in the temperature of the seal member by heating a high-pressure tank (for example, refer to Japanese Published Unexamined Patent Application No. 2006-220234).
That is, a hydrogen storing alloy accommodating container in which hydrogen storing alloy generating heat by occluding hydrogen is accommodated is connected with a hydrogen circulation channel extending from a tank main body accommodating hydrogen to a fuel cell, and further thermally connected with the tank main body through a heat pipe. According to this technique, when the temperature decreases to an extremely low temperature, hydrogen storing alloy generates heat by occluding hydrogen. This heat is transferred to the tank main body through the heat pipe, and then the tank main body is warmed.
However, in the technique proposed by the above-mentioned patent, there has been a problem that hydrogen accommodated in the tank main body is required to be supplied once to the hydrogen storing alloy accommodating container in order to warm the tank main body, which causes the device configuration to be complex and costly.